Standard Product Contact Material Options
Gemco equipment is custom manufactured with a variety of standard metallurgical options for product contact. Most machines are made in 304 or 316 grades of stainless steel, often in the "L" or low carbon variety for weld purity. Other stainless steel grades such as 317 have also been used. Other standard options are Hastelloy, often viewed as the unbreakable alternative to glass, and Inconel for severe service. Gemco will however offer units in any weldable alloy based upon the process requirements of the customer and the availability of that material and acceptable weld wire for it in the shapes and sizes (sheet, plate, bar, etc.) required. Product contact is defined as all metal surfaces inside the vessel that contact the product. Such surfaces include the cover, the valve and any internal components such as agitators, vacuum tubes, spray nozzles, etc. It must be noted however that the "L" grades of stainless are not always available in all components such as screws and bolts used inside the unit. Any such components that are not of "L" grade are never welded. Carbon steel is generally offered only in larger units when the customer's process allows it and the economics favor it. Carbon steel on smaller units is actually more expensive to manufacture due to the segregation of tools required (grinding wheels, wire brushes, etc.) from the stainless standard in our shop. Also the added cost of preparing and painting the vessel exterior offsets the initial material cost difference.

Hastelloy
In aggressive/corrosive service, when nothing else works, many industries have traditionally turned to Hastelloy C-276. Many years of outstanding performance in a variety of industrial applications have confirmed the advantages of using the alloy. Materials engineers in the chemical processing and other industries have grown accustomed to specifying its high performance based on laboratory testing, field trials and/or prior experience.

Hastelloy C-276 is a nickel-molybdenum-chromium wrought alloy that is generally considered a versatile corrosion resistant alloy. Alloy C-276 is an improved wrought version of alloy C in that it usually doesn't need to be solution heat-treated after welding and has vastly improved manufacturability.

Alloy C-276 has excellent resistance to a wide variety of chemical process environments, including strong oxidizers such as ferric and cupric chlorides, hot contaminated media (organic and inorganic,) chlorine, formic and acetic acids, acetic anhydride, and seawater and brine solutions. Alloy C-276 is resistant to pitting, stress-corrosion cracking and to oxidizing atmospheres up to 1900 degrees F.

Inconel
Inconel is a Nickel-chromium alloy. Nickel-chromium alloy Typical uses include applications that demand high strength, pressure tightness, and high resistance to destructive chemical action, mechanical wear and oxidation at elevated temperatures.

Metallurgy
Gemco equipment is typically manufactured using stainless steel as the primary metal. Others are available. Please consult factory concerning application of metallurgy and pricing.